G’nY. Are the models for controlling air pollution, like the ones being used in Norway, the United Kingdom and the United States worthy of emulation in India? Or should we reject them as incompatible with the Indian air pollution scenario?
Rakesh Kumar : Models like AERMOD (developed by USEPA), SIM-Air (developed by World Bank) and AirQUIS (developed by NILU) are developed for a specific purpose and are applicable to a region with a particular set of conditions. These models can be used in India as well to give validated results when tuned with local conditions. Further, we have been using parameters like stability classes and meteorological assumptions required by these models, which may be applicable to open fields and countryside areas of developed nations. However, the conditions in India greatly differ and hence there is a need to either tailor these models as per the Indian conditions or develop indigenous models for the country.
G’nY. How much do industries contribute to air pollution in Delhi, as opposed to sources like crematoriums, tandoor ovens, etc.? With two Delhi winters, where AQI was 999, are baby steps enough, or is keeping a check on industrial emissions the better option?
Rakesh Kumar : Source apportionment studies are generally carried out to understand the contribution of various sources in air pollution. Receptor modelling is used to identify the sources of pollution along with the measuring the extent of their contribution. Once identified and measured, a proper management plan is devised to combat the damage caused by pollution. In the case of Delhi, it is imperative to understand the impacts from distributed sectors like crematoriums, tandoor ovens, diesel generator sets etc. Keeping a check on the emissions caused by these sectors will eventually lead to better regulation of other major sectors like industries, vehicles and construction businesses.
G’nY. Is pollution from dust a minor factor in air pollution or are there other possible causes, such as construction, for increased dust loading and the consequent pollution?
Rakesh Kumar : India being a tropical country, has always been dusty and hence people have adapted differently. While change in land use pattern and increased deforestation has resulted in increased dust load, but retention of pollution is due to the regional climate of the country.
G’nY. A considerable amount of smog generated during the winters was thought to be construction dust. On November 8, 2017, the National Green Tribunal ordered an immediate halt on construction activities to curb air pollution. Could this ban reduce
Rakesh Kumar : While it is difficult to calculate the exact effectiveness of the ban on construction activities in mitigating air pollution, the ban was simultaneously implemented on biomass burning and construction activities in order to curb the pollution as it was understood that the calm conditions will trap the pollutants in the region itself and may not allow its dispersion over a wider region. IMD had predicted that the situation of wind and overall meteorology would improve over the next few days and hence the ban was implemented for a particular duration during which weather conditions would have worsened the effects of
G’nY. In 2017, a study published in Nature Climate Change stated that future ground-level ozone and PM2.5 concentrations depend on both emissions and climate change. The study calculated that with climate change, the impact on air pollution will lead to 60,000 annual deaths by 2030. What is the likelihood of this, and if correct, what do you think the Indian scenario will be like?
Rakesh Kumar : Validating the status of a single country with respect to a global level analysis like this may lead to major errors. The analysis is based on representative concentration pathways (RCPs) which have their own underlying assumptions. Further, in the case of India, it is necessary that an India specific baseline is used for such an analysis. Running a model which considers the previously recorded baseline data for parameters like emission levels, population density and respective morbidity and mortality rates can be of great assistance. However, there is an urgent need to develop an India level inventory for pollution linked morbidity and mortality cases for better analysis.
G’nY. Reports suggest that using CNG in Delhi has considerably improved the ambient air quality. But doesn’t CNG usage increase ground level ozone?
Rakesh Kumar : For improving the status of air pollution in Delhi, various policies and laws have been implemented. After the implementation of CNG since April 2001, Delhi now has the highest fraction of CNG-run public vehicles in the world. Also, a decreasing trend in SO2, CO and polycyclic aromatic hydrocarbons has been observed while studies indicate increased NOx levels. Hydrocarbons and NOx from CNG, in the presence of sunlight may result in higher ground level ozone concentration. However, there is a need for lucid analysis on CNG and other conventional fuels to assess the quality of air and to identify the source and level of ground ozone concentration.
G’nY. What do you think the future will look like for India, in terms of air pollution and associated health hazards?
Rakesh Kumar : Intense and diverse research is going on in the field of air pollution measurement, mitigation and regulation within the country. Region specific data collection, development of localised tools and techniques for pollution measurement, understanding of health hazards related to air pollution, design and development of early warning systems for air pollution are some of the key focus areas in the field. With universities like IITs, NITs and research institutes like CSIR, the field is being extensively developed for the betterment of society.